On Friday evening, Trump and the First Lady whisk up to Scotland for a weekend of golf and relaxation - and more protests outside his resort.
From challenging Western assumptions about the European Union and free trade to courting the Kremlin and North Korea's leader, Trump has delivered on his promise of an "unpredictable" US foreign policy.
May is hoping Trump's trip will boost the close ties between their two nations and help forge a future free trade deal once Britain leaves the EU.
When it comes to entourages, there can't be many much bigger than Mr Trump's.
U.S. Ambassador Woody Johnson said Wednesday that citizens are often advised to avoid public demonstrations and that he is not upset by the decision to allow the "Trump baby" balloon to be displayed near Parliament. May will host Trump and tuxedo-clad government ministers and representatives of fund managers BlackRock and Blackstone Group, as well as Arup and drinks manufacturer Diageo, for a dinner of Scottish salmon, beef and strawberries and clotted cream ice cream to discuss post-Brexit trade.
Workmen construct fences, before the US presidential visit at the end of the week, around the USA ambassador's residence in Regent's Park in London, Britain, July 10, 2018.
Donald Trump and his wife Melania on Air Force One. Relations between May, a vicar's daughter, and Trump have been strained at times.
After the visit, Trump will decamp to Finland for a one-on-one with Russian President Vladimir Putin on July 16. Some plan to stage an "all-night noise protest" outside the barricades surrounding Winfield House later Thursday, with those attending urged to "bring pots, drums and vuvuzelas".
Thousands are expected to protest across the capital, heavily led by Owen Jones" "Stop Trump' rally, which will go ahead on Friday July 13.
Yet Trump's schedule will largely keep him out of central London.
But, he added: "Whether he sees it, whether he reacts to it, we don't really care. We seem to be going into a cycle of rather regressive thinking".
The U.S. president's brash style and hardline "America First" policies have caused consternation across Britain's political spectrum and society.
"Theresa May gets a bit lost in all of that".
On Friday, May and Trump will go to to watch a joint counter-terrorism exercise by British and U.S. special forces at a military base.
But just hours after the meeting concluded he tore up a joint communique on trade, equality and the environment that May and other G7 leaders had labored late into the night to agree.
"I think that's absolutely disgusting", Eugene Bibby, who runs a domestic appliance fix shop in Tommyfield Market in Oldham, told Fox News about the balloon.